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Custom Strat Style Build – Part 3 The Pickups

March 1, 2017 Leave a comment

DIY Pickup Winder

One of the limitations which I have learned of myself is that I have limited mechanical skills. My dilemma, I want to try my hand at hand winding my own pickups but I don’t want to spend $300 for what I would consider to be a so-so winder. I was tempted to purchase the $500 winder which looks to be quite nice but I couldn’t quite convince myself that I should spend that much money on it. What to do? I’ve actually spent a couple of years now looking at the plethora of DIY winders but couldn’t quite come up with my own plan….. until now. As is the case with many problems, Harbor Freight is the answer! lol.

I came across this image on Google and that was it, this was the “plan” I was going to attempt.

diy-winder

Of course I would make this idea “my own” by using parts I had on hand. Although I purchased the Harbor Freight router speed controller, I found it to be useless for this and any other application I could imagine. The controller goes from off to full on with almost no change in the dial. I used a dimmer switch which, although not perfect, worked much, much better. I had already built this module long ago to control the speed of my 1/2″ drill when I hook it to my grain mill for home-brewing. You can see this part below in the upper left of the photo. Now that I have tested this concept, I am considering wiring the motor directly to a dedicated dimmer which (you guessed it) I happen to have on-hand.

DIY winder rudiments.

In lieu of an optical sensor, I choose to use a hall effect (magnetic) sensor for the counter module. I purchased this digital counter on Amazon and I tell you, it rocks! Best $11 I’ve spent recently.

digital-counter

The motor began life as a Harbor Freight 5″ bench grinder which set me back $35. I’m not sure if I had a coupon but 20% off coupons are ubiquitous for HF. I stripped off the grinding wheels and covers exposing the 1/2″ threaded drive shaft on both sides. The left side is reverse threaded so don’t lose the supplied bolt.

For the winding guides, I again used what I had on hand, a Harbor Freight magnetic mount. The stop collars where also purchased (you guessed it) at Harbor Freight. I purchased two packs to get two of size I needed but the other collars will be used on other project. Clearly you don’t need the magnetic mount to make a guide but I already had it and  I liked the idea that I didn’t have to a) build a support and b) it would be completely adjustable. The latter was a big plus because I was making up the plans as I went and having never wound a pickup before, I had no experience telling me how far away or how tall the guides should be. With this design, it didn’t matter I can move it anywhere I put the steel plate. To wind on the left side, I unlock the magnet mount and rotate it 180°. The trickiest part is re-adjusting the stop collar guides which would be necessary anyway depending on the type of pickup bobbin currently being wound.

To assemble the platen, I used 1/2″ plywood and the arbor plates that came with grinder. It worked out that I could use one piece (inward) as a shim. The mating piece would be reversed and held in place with the arbor nut. In this configuration very little of the drive shaft was left exposed beyond the nut. I carefully carved out a recess in the platen for the nut which would be used to drive the platen. The platen is held in place with four small neodymium magnets embedded and epoxied in place. The same setup was made for left and right posts however the left side also houses larger magnet along the rim to activate the counter each revolution. The opposing nut was an attempt to balance the weight. I was unable to weigh them but I’m guessing the magnet weighs more than the nut. Use of magnets to hold the plates on makes it simple to remove them when loading bobbins. I ended up with a 1/2″ hole in the center of each plate (don’t have to but I used a 1/2″ dowel to hold the roughed out disk and trued it up by rotating it against a sanding disc.) Instead of approximating the center of the platen each time I mount a bobbin, I made a bobbin mount out of 1/8″ ply and glued a very then piece of 1/2″ dowel to the bottom. To attach it I put double-sided tape on the bottom and align the dowel into the center hole. It isn’t “machine tight” but it does take most of the guess-work out of finding the center.

Platen detail

I used a squarish scrap board and decided to cover it with 1/8″ white board for better visibility of the magnet wire.

Click image below to watch the first test of the newly assembled device.

DIY pickup winder

Watch a short video, it spins

Three Single Coil Pickups

My first single coil bobbins

After watching as many pickup winding videos as I could stand,  I started by following the Stewmac directions for assembling the bobbins. These kits come with staggered height  pole pieces so I had to be very careful during insertion. I also had to whip together spacers and pole piece insertion/hammering tool both of which were extremely simple to make. Of course, never having used the tools, I had to remake each of them once I knew their exact purpose. Again this was easy and I took my time with the first steps.

On D-Day Saturday I spent a fair amount of time figuring out where I was going to place the spool of wire. I reasoned that most wire breaks would be caused by poor placement and consequent unnecessary tension on the wire feed. The directions pointed out that the wire should spool off the top of the spool from about 24-36″ from the winder. I found a location to clamp a length of 3/4″ dowel angled (pointed) directly at the winder/bobbin. I took my time with this and my greatest fear was stupidly walking through the wire while mounting the bobbin. Because of this I didn’t load the spool onto the dowel until the wire had been thread on to the bobbin and bobbin had been mount and I was ready to wind. Only then did I “arm” the spool.

One down and two to go.

Given these are my first pickups, I had to rely on the recommendations of other with respect on specifications. I used Alinco 5 pole pieces for the neck and Alnico 2 in the middle and bridge pickups. This solely based on the Stewmac pickup kit product pages. The Stewmac document that comes with the Schatten pickup winder provides stats on vintage and modern numbers of turns on Strat pickups all of which were south of 8,000. I decided on 7,700 for the neck, 7,800 for the middle and 7,900 for the bridge. None of these would be considered “hot” pickups but then again, I have no reason to wind hot pickups for my guitar. I play in my bedroom on a Mustang I amp. No stadium metal for me.

The neck and bridge pickups would be wound clockwise with South polarity and the middle would be wound counterclockwise with North polarity for hum canceling in the 2 and 4 switch positions. I was very fortunate to wind all three pickups with the correct number of winds (for my target) without any breaks. I was quite pleased with this first run at it!

Potting

No special equipment here. I heated water on the stove and suspended a quart canning jar of  paraffin wax in it. Once the water was close to boiling and the wax started melting, I turned the burner down. Further on I turned the stove off once all the wax was liquefied. The three pickups were submerged for 15 minutes and then one by one retrieved and the outside carefully wiped free of melting wax.

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I was a little concerned the pickups were crowded but I couldn’t think of any ill effects that resulted. If concerned the pickups could have been potted one at a time or a larger jar and more wax thrown at the problem.

Wiring the Pickguard

I love this part. Actually I loved the wiring and soldering of connections part but before I did that I decided to shield the entire pickguard with copper shielding tape. I’m not absolutely convinced that this was necessary or even wise but I just couldn’t make myself proceed without doing it. So I did and I sliced my thumb in the process. But that is typical for any day I spend in the shop!

Pickguard shielded

I found several examples of a tidy job using Google images and then used the Stewmac supplied document as the actually guide to connections. Once I was satisfied that I had done a really professional job, I attempted to fit it to my body only to discover that I had to rearrange the wires to get them to seat/fit properly. Tip: I used the cavity routing template to visualize the space and see which wires needed to be rerouted. I like my first plan but that had to be modified to work in “the real world”.

Loaded pickguard

All that is left to do is to wire in the jack and test.

Can you feel the excitement growing?

Tinkering with Electronics – Makita Drill

This has got to be one of the most boring blogs around or at least it’s getting there given that the frequency of posts have significantly declined over the last several months. And ironic it is too because playtime in my mind has been moving along non-stop. My latest rabbit-hole has been to learn all about electronics. Electrical Engineers generally start off as brilliant people and study for many, many years to become proficient, I don’t have that kind of time so I’m depending upon my high school physics to “catch-up” (teasing here). I do have some basic background knowledge but I never learned enough to actually apply of it so I’m hoping to change that this time around. If nothing else as always, I’m having fun trying.

Exploring – Makita 9.6V NiCd Drill

My Dad bought me this portable drill many years ago and it has given me good service. The drill is in great shape but I couldn’t bring myself to spend the $50 on a replacement NiCd battery pack and ultimately replaced the drill with a drill and two batteries that didn’t cost me much more than $50 combined. Since then I have purchased another new hand drill so now I was considering using the motor for my planned pick-up (coil) winder. For this session I really just wanted to confirm that the drill was still functioning normally and to do that I was going to need a 9.6 VDC power source (or similar) and I was going to have to reach the battery terminals which were located deeply inside the hand grip. I was hopeful I could use the battery charger for my power supply but to reach the terminals, I was going to have to take the drill apart.

I began by plugging in the battery charger and tested to see if I it was producing any voltage. I detected none, so I took it apart to see how it was assembled. Being a selfish and horrible blogger, I neglected to take a picture of any of findings but I can describe them. Here is a picture of an identical charger to mine, the picture is not mine. You’ll notice that there are two switch buttons, yellow for reset and red for charge. There is also a red LED to indicate the unit is charging. You can see the + and –  molded into the case indicating how the battery pack should be inserted and you’ll notice the  “key slot” on the negative side of pack prevents inserting it backwards. What you can’t see from this photo is there is a third metal contact which connects a circuit to a thermister which is wired to the first battery in the battery pack. The NiCds are shot but I salvaged the thermister.

Makita-Charger

I’m not an EE but clearly this is to monitor the charging circuit so that when the battery reaches a certain max temperature, charging is stopped. How does the thermal protection circuit work? I’m not sure, I haven’t looked it up yet but it didn’t stop me from taking the thing apart and digging deeper inside.

Four screws and the top comes off easily to reveal a pristine 120 VAC to 12 VAC transformer. Next in the circuit was a 4 pronged chip on a heat sink labeled RBV-401. Google is my friend and I was able to pull up a data sheet on it. It is a bridge rectifier which is a very common method for converting AC current to DC current using a network of 4 diodes. Hey, he DID learn something over the last month!

RBV4 Rectifier

So looking at the pin outs I can see the 12 V AC are on the center pins with the VDC on the outer two pins. Using my meter I now see a nicely stable 10 VDC are being generated. Time to wire this to my drill to see if I can make the motor run.

Dis-assembly of the drill was quite straightforward. I removed a  series of screws and carefully separated the two halves.

IMG_3659

I wired up some leads to the outer pins of the rectifier and established that the drill motor was functioning perfectly. Although I knew the drill battery packs were rated at 9.6 VDC, I was curious what voltage  the motor was rated for. Again I Googled the part number on motor RS-750SH and by all indications it was a 12 VDC motor. I decided to hookup a spare 12 VDC power supply I had floating around and again the motor performed well. I realize that things could change when/if the drill was under load and at this point I have no idea about how many amps this thing would need to function as a drill. I don’t think it would pull very many amps however just spinning a bobbin around to wind a pickup.

IMG_3662

Having had enough fun for one day, I decided to close the drill back up for safe keeping. I haven’t yet decided if I want to use the drill as a drill or if I want to sacrifice it for another project. It seems a bit of a waste to destroy a perfectly functional drill. Another option might be to retrofit a battery pack or even to convert it to a corded drill. I can’t decide, what do you folks think I should do?

You have been reading an excerpt from the shop journal of the Turtlecovebrewer.

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